ORLANDO, FL, USA (UroToday.com) - This study aimed to provide a better understanding of the differences between primary androgen deprivation therapy (PADT) in the U.S. and Japan as a direct comparison study.
The U.S CAPsure registry identified 1 934 men treated with PADT; the Japanese J-CaP identified 16 300 men treated with PADT. The men in Japan were slightly older and had a higher-risk disease (mean J-CAPRA score 3.0 vs. 2.1, p > 0.001). Adjustments were made for disease risk and the type of androgen ablation. Men in Japan had better overall survival. Researchers at UCSF concluded these findings support existing PADT guideline use in Japan. They cited dietary and environmental factors as well as possible comorbidity variables as reasons for the significant differences of varying biology of prostate cancer between Japanese and U.S. populations.
Listen to Matthew R. Cooperberg, MD, MPH speak about the study
Partial Transcript:
"This study was a comparison study between CaPSURE (a large registry of men treated across the United States, mostly in community practice, with all different types of treatment for prostate cancer) and the J-CaP registry (a Japanese registry which accrued men treated with primary hormonal therapy -- roughly 50% of all the men in the country with prostate cancer) from 2001 to 2003. In this study, we looked at the outcomes of hormonal therapy, given as monotherapy.
“Prostate cancer is a very different disease in the United States from Japan. Until recently, there was very little screening for prostate cancer in Japan, and as a result --- or at least in part as a result -- men in Japan are much more likely to have aggressive disease or high-stage disease, at time of diagnosis. Hormonal therapy has been much more the mainstay of treatment in Japan, however, we have known from previous studies in CaPSURE and elsewhere that hormonal therapy is also used very commonly as monotherapy in the United States. Now, here we call that under treatment. We have a number of studies suggesting that men with intermediate- and high-risk disease really do benefit from surgery, radiation, and other treatments, even when men are older, and survival is better. Furthermore, men with high-risk disease really shouldn't just get hormonal therapy alone; conversely, men with low-risk disease should really be on active surveillance. So there's not much of a defined role for hormonal therapy, as monotherapy, for localized disease in the U.S. That is consistent with U.S. and European practice guidelines, but the Asian guideline is different. The Asian and NCCN prostate guideline actually does endorse hormonal therapy as a treatment option for localized prostate cancer.
“The goal of this study was to look at the outcomes, between these two populations, on either side of the Pacific. We basically focused on overall survival, comparing men in J-CaP (on the Japanese side), and men in CaPSURE receiving primary androgen deprivation therapy. If you adjust for risk (we adjusted for the J-CaP score which is a validated score intended for use among men with high-risk and advanced prostate cancer) using J-CaP, or adjust for the year of diagnosis, for the type of hormonal therapy used, the type of practice, and comorbidity, we found almost a three-fold difference in survival favoring the Japanese patients compared to the American patients when treated with ADT monotherapy. The other interesting finding was that combined androgen blockade had a beneficial impact in terms of survival only in the Japanese cohort, but not in the U.S. cohort.
“I think these findings are, first of all, important for clinical practice. (This data) actually seems to support both (U.S and Asian) sets of guidelines, suggesting hormonal therapy remains a suboptimal treatment for localized prostate cancer in the U.S. In contrast, it is probably actually correct that (PADT) is endorsed on the western side of the Pacific, in Asia, because the patients there really do seem to do better with it. Now of course the question is, ‘Why?’ Is this genetics? Is this diet and environment? Is there some other unmeasured confounding factor that we don't know about? The answer is probably that it is a combination, and that there's some combination of genes and environmental factors and dietary factors that explain this. I think the more that we can understand prostate cancer as a global disease and the way it varies from place to place, country to country, in light of different screening practices, different diet and environmental factors, different genetics, the better we're going to understand the way to best manage the disease, both in the U.S. and abroad.”
Presented by Matthew R. Cooperberg, Shiro Hinotsu, Mikio Namiki, Peter Carroll, and Hideyuki Akaza at the 2013 Genitourinary Cancers Symposium - February 14 - 16, 2013 - Rosen Shingle Creek - Orlando, Florida USA
University of California, San Francisco, San Francisco, CA; Department of Pharmacoepidemiology, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan; Department of Urology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
Prepared by Karen Roberts, medical writer for UroToday.com
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